|Mode or source||Percentage of total||All oil spills (gallons)|
|Maritime tank vessels||37.4||7,245,027|
|Maritime no tank and other vessels||18.5||3,584,388|
|Highway, rail, and other transportation||1.5||285,191|
|Nontransportation structures and facilities||3.7||723,172|
|Unknown and other||6.7||1,299,139|
NOTE: Data are preliminary.
SOURCE: U.S. Department of Transportation, Bureau of Transportation Statistics, calculations based on U.S. Department of Homeland Security, U.S. Coast Guard; Pollution Incidents In and Around U.S. Waters, available at http://www.uscg.mil/hq/g-m/nmc/response/stats/ad.htm, as of October 2003.